Heat-stable high-amylopectin starch

ABSTRACT

The invention relates to starch used in the baking-industry. Creams, (fruit-) fillings, toppings, glazes and other bakery products are often thickened by the inclusion of a certain amount of starch as binder, filling or thickening agent, for example providing gel-strength, viscosity, glaze, texture or creaminess to the cream or filling. Commonly used starches have insufficient stability to for example heat applied during baking. The invention provides a starch-containing filling or topping for a bakery product wherein said starch comprises a tuber or root starch containing less than about 5% amylose and use of such a filling or topping for improving a bakery product. Furthermore, the invention provides a heat-stable starch and bakery products comprising a heat-stable starch.

The present application is a continuation of, and claims priority to,U.S. application Ser. No. 09/743,491, having a filing date of Mar. 23,2001 now abandoned.

BACKGROUND OF THE INVENTION

The invention relates to starch used in the baking-industry instarch-containing fillings or toppings, such as bakery cream, Swisscream, fruit filling, savoury or sweet pie filling, almond pastefilling, choux pastry filling, pizza topping, glazes on pastry or snacksand such.

Creams, fruit- or piefillings, toppings, glazes and other fillings ortoppings for use in bakery products are often thickened by the inclusionof a certain amount of starch as binder, filling or thickening agent,for example providing gel-strength, viscosity, glaze, texture orcreaminess to the cream or filling.

Many factors influence a decision to apply a particular ingredient oradditive in a bakery product. These may include functional properties,cost or, perhaps most importantly, the regional preference for taste,mouth feel and texture. Moreover many different processing technologiesare used in the baking industry also affecting the properties of thebakery product.

Starches are widely applied in fruit fillings, creams, other fillings,topics and glazes often in conjunction with hydrocolloids such asalginates, pectin, gelatin and others. In cold prepared fruit fillings,a starch should provide clarity, rapid viscosity built-up and a smoothshiny appearance. If a pulpy, more fruity appearance is required thiscan be achieved by applying coarser products. In cook up preparationsthe clarity and shininess are of importance as well and a partial pectinreplacement is sometimes possible.

SUMMARY OF THE INVENTION

In bakery creams, starches should impart high viscosity, and a creamysensation in the mouth as well as give a creamy and shiny appearance.For almond paste fillings, coarsely ground instant starch derivativesare often applied. And for savory fillings such as in pizza toppings awide range of derivatives is known.

In all these applications the filling or topping should have a certainresistance towards the baking process. For instance, if a bakery creamlooses its viscosity during the baking the cream simply runs out of theproduct giving the product an unpalatable appearance.

Often, in a bakery cream, apart from starch derivatives, otherhydrocolloids, in particular alginates, are applied for the gellingproperties. The baking stability of a cream may be improved by applyingan alginate with a higher temperature resistance. However, this leads toproducts with a less desirable texture, often being somewhat foamy orsometimes being even brittle after baking, therefore, preferablyalginates or other heat-stable hydrocolloids are used sparingly asadditives to a bakery product.

Today's industry becomes increasingly demanding of derivatives used inbakery products with respect to baking stability, and acid- and shearstability. Modern bakeries work with high temperatures, e.g. 30 minutesbaking at 200° C. is not uncommon, still the cream, topping, glazing orfilling should not run out. In general, waxy corn starches andderivatives thereof are used in bakery products, since these tend tohave a somewhat higher baking stability than (derivatives from) commonpotato starch or common corn starch, which are commonly used in the foodindustry, despite the fact that corn starches in general are lessviscous and thus need to be applied in higher dose, and often have aprominent, not always appreciated taste, which is an additionaldisadvantage over potato starch. Furthermore, even waxy corn (maize)starch looses its stability, gel-strength or viscosity under most oftoday's baking conditions, demonstrating that heat-stable starches areneeded.

The invention provides a starch-containing filling or topping for abakery product wherein said starch comprises a tuber or root starchhaving an amylopectine:amylose ratio of at least 90:10, preferably atleast 95:5, more preferably at least 99:1.

Starches, both of the common variety containing both amylose andamylopectin, obtained from cereals or from tubers or roots and of thewaxy variety, obtained from cereals, are widely used in foodstuff.

DETAILED DESCRIPTION OF THE INVENTION

Common starch consists of two major components, an, in essence, linearα(1-4)D-glucan polymer (branching is found at a low level) and anelaborately branched α(1-4 and 1-6)D-glucan polymer, called amylose andamylopectin, respectively. Amylose has, in solution, a helicalconformation with a molecular weight of 10⁴-10⁵, or higher. Amylopectinconsists of short chains of α-D-anhydroglucopyranose units primarilylinked by (1-4) bonds with (1-6) branches and with a molecular weight ofup to 10⁷, or higher.

Amylose/amylopectin ratios in native starches in plants are generallyanywhere at 10-40 amylose/90-60% amylopectin, also depending on thevariety of plant studied. In a number of plant species mutants are knownwhich deviate significantly from the above mentioned percentages. Thesemutants have long been known in maize (corn) and some other cereals.Waxy corn or waxy maize has been studied since the beginning of thiscentury. Therefore, the term waxy starch has often been equated withamylose free starch, despite the fact that such starch was in generalnot known from other starch sources such as potato but mainly derivedfrom corn. Furthermore, industrial use of an amylose free potato starch(containing essentially only amylopectin molecules) has never occurred,certainly not on the large scale and with such a wide range ofapplications as seen with waxy starch from corn.

The invention now provides a filling or topping for a bakery productwherein said starch comprises a tuber or root starch having aamylopectine:amylose ratio of at least 90:10, preferably at least 95:5,more preferably at least 99:1 having improved stability over fillings ortoppings commonly used in the baking industry. Said improved stabilityfor example relates to freeze-thaw stability or storage of the fillingor topping. In a preferred embodiment of the invention a filling ortopping is provided having improved heat stability over fillings ortoppings commonly used in the baking industry. (A tuber or root starchhaving a amylopectine:amylose ratio of at least 90:10, preferably atleast 95:5, more preferably at least 99:1 is herein also called aheat-stable starch).

In a preferred embodiment a filling or topping according to theinvention is provided wherein said tuber or root starch comprises apotato starch. Amylose production in a plant is among others regulatedby the enzyme granule-bound starch synthase (GBSS), which is involved ingenerating the amylose content of starch, and it has been found thatmany of the available waxy plant mutants lack this enzyme or itsactivity, thereby causing the essentially exclusive amylopectincharacter of these mutants. Although in general not (yet) industriallyused, amylose free potato mutants are available for starch production,producing a starch containing essentially only amylopectin molecules.

An example of a heat-stable starch provided by the invention is a starchobtained from an amylose-free potato plant which is for example lackingGBSS activity or GBSS protein altogether, thereby lacking amylose andhaving essentially only amylopectin molecules.

In another embodiment of the invention a filling or topping is providedwherein said tuber or root starch is derived from a genetically modifiedplant such as a potato, yam, banana or cassava having reduced amylosecontent or comprising essentially only amylopectin molecules. Geneticmodification of plants is a skill available to the artisan, and forexample involves modification, deletion of or insertion in or(antisense) reversion of (parts of) a gene, such as a gene encodinggranule-bound starch synthase (GBSS), which is involved in determiningthe amylose content of starch. In order to manipulate such crop plants,efficient transformation systems and isolated genes are available,especially of potato, and others are found by analogy. Traits, such asabsence of amylose, that are introduced in one variety of a crop plantcan easily be introduced into another variety by cross-breeding.

In the experimental part of this description, a filling or topping for abakery product is provided comprising a heat-stable starch obtained froma genetically modified or amylose-free potato. Use of starch fromgenetically engineered crops has in general been suggested from the timeon it was possible to genetically modify such crops (see i.e.Bruinenberg et al., Chemistry and Industry, Nov. 6, 1995, page 881-884;de Vries, Foodmarketing and Technology, April 1997, page 12-13)).Specific use of amylopectin-type potato starch as filling or viscosityagent in canning has been suggested in WO/97/03573 to prevent undesiredresidual viscosity seen with commonly used starch. Furthermore, EP 0 796868 suggests use of a hydroxypropylated and cross-linked waxy potatostarch to increase the viscosity of a food product.

However, none of these provide indications on how to avoid usingstarches in today's baking-industry which generally have low- orinsufficient stability to heat and compromise at least the palatability,texture, appearance or other related aspects of baking products.

In a much preferred embodiment of the invention a filling or topping isprovided wherein said heat-stable tuber or root starch is a cross-linkedstarch such as a di-starch phosphate or a di-starch adipate.Crosslinking starch is in itself a method available to the artisan,various cross-linking agents are known, examples are epichlorohydrin,sodium trimetaphosphate (STMP), phosphorous oxychloride (POCl₃),acrolein, adipic anhydride (Adip) or other reagents with two or moreanhydride, halogen, halohydrin or epoxide groups or combinations whichall can be used as crosslinking agents. Typical and often preferredexamples of such a cross-linked starch are di-starch-phosphate ordi-starch-adipate.

In yet another embodiment of the invention a filling or topping isprovided wherein said tuber or root starch is a stabilised starch suchas a starch acetate. Stabilisation by hydroxyalkylation of starch is forexample obtained with reagents containing a halogen, halohydrin, orepoxide group as reactive site. Other reagents are for example 1-octenylsuccinic anhydride, sodium tripolyphosphate, potassium orthophosphate,sodium orthophosphate or orthophosphoric acid.

In one embodiment of the invention said starch is stabilised byhydroxypropylation, for example using propylene oxide. In a preferredembodiment of the invention, said starch is a stabilised starch in whichsome or all of the available hydroxyl groups of the amylopectinmolecules have been esterified by acetyl groups. The addition of acetylgroups is generally done in aquous suspensions of starch using aceticanhydride, succinic anhydride or vinyl acetate as reactants underalkaline conditions. A typical and often preferred example of such astabilised starch is a starch-acetate.

Crossbonding and/or stabilising reagents are reacted with starch underalkaline conditions. Suitable alkali materials are: sodium hydroxide,potassium hydroxide, ammonium hydroxide, magnesium hydroxide, sodiumcarbonate and trisodium phosphate. Preferred are the alkali metalhydroxides and carbonates, most preferred are sodium hydroxide andsodium carbonate. Sometimes salts are added as to prevent swelling underalkaline reaction conditions. Preferred are sodium chloride and sodiumsulfate.

Crossbonded starch acetates comprised in a heat stable starch providedby the invention in general have an acetyl content which corresponds toa DS or degree of substitution of 0.001 to 0.2, preferably from 0.03 to0.092, most preferably from 0.05 to 0.092. The term DS used hereinindicates the average number of sites per anhydroglucose unit of thestarch molecule in which there are substituent groups.

Crossbonded hydroxypropylated starches comprised in a heat stable starchprovided by the invention have in general a hydroxypropyl content whichcorresponds to a DS of 0.001 to 0.3, preferably, 0.03 to 0.21, mostpreferably 0.06 to 0.21. Heat-stable distarch-acetate may for example becrossbonded with 0.001 to 0.024% of adipic anhydride, preferably with0.01 to 0.12%. Prior to crossbonding with adipic anhydride the starchmay be treated with hydrogen peroxide and/or peracetic acid. Preferablywith a quantity which corresponds with 0.001% to 0.045% of activeoxygen, most preferably with 0.005 to 0.45%. Heat-stable distarchphosphate may for example be crossbonded with sodium trimetaphosphate upto such a degree that the residual phosphate is no more than 0.14% foran amylopectin potato starch or 0.4% for other root and tuber starches.Preferably the starch is crossbonded with 0.01% to 0.25% of sodiumtrimetaphosphate, most preferably with 0.25 to 0.15%, under conditionsknown to the artisan. Of course it is always possible for the artisan tofind conditions in which the reactants react with a very low yield,outside of the preferred conditions resulting in heat-stable starcheswith the derived properties.

Heat-stable distarch phosphate may as well be crossbonded withphosphorous oxychloride up to such a degree that the residual phosphateis not more than 0.14% for an amylopectin potato starch or 0.4% forother root and tuber starches. Preferably the starch is crossbonded with0.0001% to 0.01% of phosphorous oxychloride, under conditions known tothe artisan. Of course it is always possible for the artisan to findconditions in which the reactants react with a very low yield, outsideof the preferred conditions, resulting in heat-stable starches with thederived properties.

In a preferred embodiment a filling or topping comprising a heat-stableinstant starch is provided by the invention, which for example allowsapplication in cold-prepared fruit fillings to bind fruit juice or inbakery jams and application in cold-mix bakery creams, providing a highviscosity and a smooth creamy texture. Furthermore, the inventionprovides use of said heat-stable instant starch in instant pastry orcake mixes and such.

In general starch and starch derivatives for the food industry areinsoluble in cold water. Viscosity and water binding is achieved byheating or cooking. These starches are referred to as cook-up starches.For convenience starches are sometimes pregelatinised i.e. precooked anddried. These starches are referred to as instant starches and performwithout heating or cooking in the food stuff. Pregelatinisation can beachieved by spray cooking, spray drying, roll drying, drum drying,extrusion, heating in aqueous water miscible organic solvents or underhigh pressure or with other methods known in the art.

Provided by the invention is for example a filling or topping whereinthe starch present is a tuber or root starch having anamylopectine:amylose ratio of at least about 90:10. Such a filling ortopping is for example further composed of non-starch products such asmeat, eggs, milk, aroma's, and finds for example application in savourysnack fillings or toppings wherein a heat-stable starch according to theinvention is the only starch source. In such a topping or filling, alsoother desired properties of a starch in general may be used to arrive ata product with palatable texture and appearance.

The invention also provides a filling or topping comprising a heatstable starch according to the invention which is further comprising astarch having an amylopectine:amylose ratio of less than 90:10. Ingeneral, fruit fillings comprise fruit or fruit remains that contain theusual starches not having amylopectine:amylose ratio's found in heatstable starches. It is furthermore possible to use commonly usedstarches in fillings or toppings to provide the product with certain,for example desired viscosity characteristics next to using aheat-stable starch according to the invention to arrive at a desiredstability. Moreover, products, such as fillings containing for examplepotato mash or even potato slices for savoury snacks will benefit fromusing a heat-stable starch according to the invention, having beenprovided with better stability, for example upon baking.

In yet another embodiment of the invention a filling or toppingaccording to the invention is provided further comprising a hydrocolloidsuch as an alginate pectin or gelatin. In the experimental part it isdemonstrated that for example the gel strength and resistance to bakingof a bakery product such as a bakery cream or fruit filling, preparedwith a heat stable starch according to the invention is in generalhigher than the gel strength of a bakery cream prepared with commonpotato starch or waxy maize starch despite the fact that the viscosityof the different starches in the various preparations is about the sameor at least comparable. This results in very favourable bake-outpercentages. For example, in bakery cream comprising a hydrocolloid suchas an alginate which is not highly stable upon baking, a heat stablestarch according to the invention shows far superior baking stability(bake-out percentages i.e. 2, 11, 9, 16) over the baking stabilityobtained with common potato starch (31, 28, 26) and waxy maize starch(24, 18).

To get comparable results with common potato starch or waxy maizestarch, it is necessary to include a much more heat-stable hydrocolloidin the recipe. Only than it is possible to obtain bake-out percentagesfor these products (i.e. 9, 9, 8, 8, 2) that are obtained with aheat-stable starch according to the invention using a more modestlystable hydrocolloid.

The invention furthermore provides use of a tuber or root starch havingan amylopectine:amylose ratio of at least 90:10 for producing a fillingor topping for a bakery product, for example for improving the bakingstability of a starch-containing filling or topping for a bakery productsuch as a bakery cream, fruit or pie filling, topping or glaze. Such usecomprises adding to said filling or topping a heat-stable starchaccording to the invention for example containing less than about 10-5%amylose molecules. Herewith the invention provides a method wherein thetexture and palatability of said bakery good comprising such a cream,(fruit-) filling, topping or glaze after baking is improved over atexture and palatability seen when using commonly used starches orstarch derivatives.

For example, as demonstrated herein in the examples, a heat-stablestarch providing stability as provided by the invention provides farbetter gel-strength or viscosity after baking (expressed as bakingstability, bake-out or as the ratio of viscosity before and afterbaking) to a bakery cream or fruit filling than commonly used starchesdo. This not only gives the bakery product a taste advantage overcommonly used waxy corn starch but also allows for reducing the starchdosage that is considered necessary altogether or allows for using lessalginates, or using only modestly heat-stable alginates, allowing forinexpensive production of bakery goods.

In a preferred embodiment the invention provides use according to theinvention wherein said tuber or root starch comprises a potato starch.Use of heat-stable starch as provided by the invention is preferablydone with root or tuber-derived amylose-free or amylopectin nativestarches such as obtainable from potato starch, tapioca, sweetrootstarch, yam starch, canna starch or manihot starch. In one embodiment ofthe invention such a tuber or root starch is derived from an amylosefree potato mutant, as described above. In another embodiment of theinvention such a root or tuber starch is derived from a geneticallymodified plant, for example from a genetically modified potato plantvariety. Examples of such a potato plant variety are the variety Apriorior Apropect, or varieties derived thereof.

The invention also provides use of a heat stable starch according to theinvention in a bakery cream, where it provides excellent bakingstability, reducing bake-out percentages as explained above and use of aheat stable starch in a fruit filling, reducing viscosity loss orimproving viscosity upon baking.

The invention furthermore provides a bakery product comprising astarch-containing filling or topping according to the invention.Examples of such bakery products vary from savoury snacks to pastry, andfrom pizzas to fruit pies, and include pre-made or ready-made bakerycream, pre-made filling such as a fruit- or pie-filling, topping, glaze,pastry or cake mix comprising a heat-stable starch according to theinvention. These, and many other comprising a topping or fillingcomprising a heat stable starch have improved appearance and textureover products made with commonly used starches.

The invention furthermore provides a tuber or root starch having anamylopectine:amylose ratio of at least 90:10 for use in a filling ortopping for a bakery product. In a preferred embodiment, said starch isa potato starch, as exemplified in the experimental part of thedescription.

Also, the invention provides use of heat-stable starch or derivativesderived from said starch in bakery products and bakery half-products. Inaddition the invention provides a method for providing heat-stability tobakery cream, (fruit) filling, topping, glaze, pastry mix or cake mixcomprising use of heat stable starch or derivatives derived from saidstarch. The baking stability of a cream or other product may now beimproved by applying a heat-stable starch according to the inventioninstead of by applying an alginate or other hydrocolloid with a highertemperature resistance, or by using excess alginate, therewith nowavoiding end-products with a less desirable texture due to thehydrocolloid content.

The invention is further explained in the experimental part of thisdescription without limiting the invention thereto.

Experimental Part

Methods

Starches used are common potato starch (PS), waxy corn (maize starch(WMS) and amylose free or amylopectin potato starch (APS) containingessentially only amylopectin molecules.

Recipe Instant Bakery Cream I:

% g Instant modified starch 20.00 80.0 Whole milk powder 30.00 120.0Powdered sugar 47.50 190.0 Alginate blend* 2.25 9.0 Colour/vanillaflavour 0.25 1.0 *Lacticol F336 which less stable towards baking orLacticol F616 which is more stable and known to cause less bake-out.(Supplier Danby food ingredients.)Preparation Procedure:

-   -   The dry ingredients are blended.    -   The powdered mix (400 g) is added to 1000 ml tap water and        stirred for 3 minutes using a Hobart mixer (high speed).        Recipe Instant Bakery Cream II:

% g Instant modified starch 122.50 90.0 Powdered sugar 42.50 170.0Dextrose monohydrate 10.50 42.0 Low fat milk powder 16.75 67.0 Vanalata*6.00 24.0 Alginate blend* 1.50 6.0 Colour/vanilla flavour 0.25 1.0*Supplier Kievit **Lacticol F616Preparation Procedure

-   -   The dry ingredients are blended.    -   The dry mix is added to 1000 ml of tap water and stirred in a        Hobart mixer for:

-   1 minute level 1

-   1 minute level 2 and

-   30 sec at level 1    Recipe Fruit Filling III

% g Powdered sugar 7 15 Instant modified starch  3, 7 8 Apple juice 89,3 192Preparation Procedure

The dry ingredients are blended. The powdered mix (23 g) is added to theapple juice (192 g) and stirred with a hand mixer at speed 1 for 20seconds. The viscous mass is transferred to a 250 ml beaker and placedin a temperature controlled waterbath at 20° C. for 30 min.

Baking Stability for Recipe I and II, Expressed as Percentage Bake-out

Baking stability is measured by measuring the bake-out (liquefaction andsubsequent elongation of the diameter during and after the bakingprocess) of a slice of bakery cream of 6.3 cm upon baking for 10 (recipeI) or 20 min (recipe II) at 200° C. Bake-out is expressed as thepercentage of elongation of the diameter of saidslice of bakery creamseen after baking. The lower the percentage bake-out is, the better isthe baking stability of the cream.

Baking Stability for Recipe III

The viscosity of the filling is measured with a Brookfield LVF. Themixture is baked in an oven at 175° C. for 45 min. The viscosity ismeasured again. The baking stability is expressed as the ratio of theviscosity before and after baking. The lower the ratio the better thebaking stability.

Gel Strength

Gel strength is measured using a Brookfield HAT or a Stevens.

Results

TABLE 1 Properties of products A–I in recipe I using Lacticol F336(Brookfield HAT) Viscosity Bake-out Product Starch Modification mPas % APS STMP/Ac 120000 31 B PS STMP/Ac 118000 28 C PS STMP/Ac 114000 26 D WMSAdip/Ac 100000 24 E WMS Adip/Ac 128000 18 F APS Adip/Ac 174000 2 G APSAdip/Ac 164000 11 H APS STMP/Ac 158000 9 I APS Adip/Ac not meas. 16

TABLE 2 Properties of products A–H in recipe I using Lacticol F616(Brookfield HAT) Viscosity Bake-out Product Starch Modification mPas % APS STMP/Ac 136000 9 B PS STMP/Ac 146000 9 C PS STMP/Ac 127000 8 D WMSAdip/Ac 129000 8 E WMS Adip/Ac 134000 2 F APS Adip/Ac 171000 0 G APSAdip/Ac 160000 0 H APS STMP/Ac 182000 2

TABLE 3 Properties of products A–H in recipe II using Lacticol F33(Stevens) Bake- Bake- Viscosity out¹ Viscosity out² Product StarchModification mPas % mPas % A PS STMP/Ac 130 55 200 51 B PS STMP/Ac 13055 220 55 C PS STMP/Ac 130 60 200 62 D WMS Adip/Ac 150 54 220 55 E WMSAdip/Ac 140 47 210 50 F APS Adip/Ac 230 21 330 17 G APS Adip/Ac 220 34330 28 H APS STMP/Ac 210 24 300 22 ¹Bake-out was measured of bakerycream baked directly after preparation. ²Bake-out was measured of bakerycream baked one hour after preparation.

TABLE 4 baking stability of products in recipe III Viscosity mPasProduct Starch Modification before after ratio A PS STMP/Ac 2180 39200,6 B PS STMP 7780 6080 1,3 I APS Adip/Ac 960 8140 0,2 J APS Adip/Ac3600 13400 0,3 K PS Adip/Ac 5940 8700 0,7

1. A method for providing baking stability to a filling or topping of abakery product comprising i. adding an acetylated potato starch that hasbeen crosslinked with adipate, wherein said starch has anamylopectin:amylose ratio of at least 99:1 to said filling or topping;ii. combining said filling or topping obtained in step (i) with saidbakery product to form a combined product; and iii. baking said combinedproduct whereby improved baking stability of the filling or topping isachieved as compared to products containing common potato starch andwaxy maize starch, wherein baking stability is measured by percentbake-out of the filling or topping after baking occurs, and wherein alow percentage of bake-out results in greater baking stability.
 2. Amethod according to claim 1, wherein said starch is from a plantgenetically modified to provide reduced amylose content.
 3. A methodaccording to claim 2, wherein said plant has been genetically modifiedby one of modification of, deletion of, insertion in, or antisensereversion of, parts of a gene encoding granule-based starch synthase insaid plant.
 4. A method according to claim 1, wherein said starch is aninstant starch.
 5. A method according to claim 1, wherein said topping,or filling is selected from the group consisting of bakery creams, Swisscreams, fruit fillings, savoury or sweet pie fillings, almond pastefillings, choux pastry fillings, pizza toppings, glazes, pastry mixesand cake mixes.
 6. A method according to claim 1, wherein said bakeryproduct is selected from the group consisting of savoury snacks,pastries, pizzas, fruit pies and cakes.
 7. A method according to claim1, wherein said filling or topping is a bakery cream or fruit filling.8. A method according to claim 1, wherein said combined product is bakedfor 20 minutes at a temperature of 200° C.
 9. A method according toclaim 1, wherein said combined product is baked for 45 minutes at atemperature of 175° C.
 10. A method according to claim 1, wherein aidcombined product is baked for 10 minutes at a temperature of 200° C.